We are attempting to create and develop new drugs of the anthracycline type which act to inhibit the development of cancers in animals after the animals have been inoculated with oncorna viruses. A variety of natural product anthracyclines have been studied such as adriamycin, daunorubicin, cinerubin, nogalamycinm carminomycin, aklavin. From the data obtained we have created a variety of new synthetic anthracyclines and compared their activity with our in vivo animal model and a variety of relevant enzymes. Inhibitors of some enzymes such as reverse transcriptase appear to be active in preventing some cancers. In the most successful experiments, new drugs we have created can suppress the formation of up to 95% of cancers that would be otherwise expected to develop following oncorna virus inoculation.